fn destroy_box(c: Box<i32>) {
    println!("Destroying a box that contains {}", c);
}

fn main() {
    println!("Hello, world!");
    let x = 5u32;
    let y = x;
    println!("x is {}, and y is {}", x, y);

    let a = Box::new(5i32);
    let b = a;

    // println!("a contains {}", a);

    destroy_box(b);

    println!("b contains: {}", b);
}
